Putting Estimates together for offers / Door knocking Offers

[Timothy Stanley]

1. When you go door knocking how do you make a legit offer on a house that that makes sense but you don't know much about the house?

2. House are going quick.. If I want to make an offer on the house that needs rehab work; what is the best way to put a pretty close estimate together without bidding it out and not screwing myself?